Technical Field
The present disclosure pertains to apparatus, systems and methods for providing power to electric vehicles and other electrical objects or systems using a mobile energy storage apparatus that has variable power inputs and outputs.
Description of the Related Art
At the time of this writing, the combustion engine is the most common form of propulsion for land vehicles, water craft, and aircraft. The most common combustion engines are fueled by petroleum or other fossil fuels, which are in limited supply on this planet. It would be advantageous to have a flexible solution for propulsion that does not rely on one energy source.
Electricity is an option and there are many methods of producing it. Whereas combustion fuels rely on limited supply or limited land area to grow fuel, electricity generation has a number of sources including but not limited to: wind, solar, tidal, wave, geothermal, nuclear, coal, natural gas, diesel, gasoline, and more. High levels of electrical power can be nearly instantaneously transmitted long distances through small conductors in a safely controlled manner and generally with little or no sound. For these and other reasons, almost all modern lighting is based on electricity instead of combustion as it was in years past. Similarly, residences and other buildings and facilities are primarily powered by electricity that is brought in by wire from power stations instead of local combustion sources.
In some stationary and many mobile situations where an electric vehicle, craft, device (such as a portable welder) or residence or other electrically powered facility is not positioned near a permanent or reliable electrical power source, a common method for delivery of electricity is from a combustion engine generator. This is also the most common option for most homeowners who want a backup power solution available for emergencies. Some residences and other facilities have a solar or wind power system that usually has a backup generator and/or a large, heavy and stationary battery backup system. For much of their lifetime, these backup systems just sit unused. Furthermore, they are bulky, heavy, and designed for stationary use rather than being mobile. In limited cases where an auxiliary power system uses clean and quiet sources, such as solar, is mobile, as in U.S. Pat. No. 7,795,837 B1: “PORTABLE SOLAR POWER SUPPLY TRAILER WITH A SECURITY CONTAINMENT AREA AND MULTIPLE POWER INTERFACES”, it is limited to supplying standard AC service voltage (110-240 VAC) and very low voltage DC power (below 54 VDC) and due to the trailer's size it still needs to be towed using a vehicle that would most likely be fueled by a liquid petroleum fuel to have the range and power to tow the trailer to the site. This reference does not consider being able to move a backup power generation or storage system to wherever it was needed or desired, thus greatly increasing its ability to be useful. Such a transportable system could also not be limited to providing standard AC service voltage and low voltage DC power and could instead also provide additional energy at higher voltages and currents to an electric vehicle and extend its range.
Furthermore, as the population increases and electrical demands increase and fluctuate, there is an increasing need for electrical load-leveling and management capabilities, and it would be advantageous for there to be more distributed power generation and storage capacity. Additionally, when military or other operations require remote power generation, current systems use a hot, exhaust emitting, and loud combustion generator that is powered from a flammable fuel source.
Applications, such as land and water transport where the power source moves with the vehicle, rely almost exclusively on an onboard combustion process to provide mechanical and/or electrical power. As the population increases and vehicle use rises, there is increasing interest in electric propulsion. Unfortunately, the use of electric vehicles (EVs) is traditionally limited either by wires that run overhead or underneath the electric vehicle or by energy stored in batteries, fuel cells, or other onboard storage means. At the time of this writing, fuel cells are extremely expensive as are the best batteries and ultra capacitors. Furthermore, most fuel cell systems require supplemental batteries to augment the power output and assist during the system start-up phase (especially in colder temperatures).
A characteristic of an electric vehicle's battery pack is that the voltage does not always remain at one constant level. As the electric vehicle's battery pack is depleted the available voltage drops and overall power is reduced. Also, heavier electric vehicles require more power for movement, thus consuming more energy. This all relates to Ohm's Law, which states that Voltage (V) multiplied by Amperage (I) equals Power (P). Additionally, a battery or battery pack does not perform as well when higher amperage is demanded. In fact, the voltage tends to drop lower and lower the more the amperage increases. Since total power is the product of the system voltage and amperage (P: V·I), it turns out that the higher the system voltage the less amperage is needed for any given amount of power.
Due to the current state of battery and fuel cell technology, and because common combustion engine fuels like gasoline or diesel carry so much more energy per weight and volume than batteries or fuel cells, electric vehicles including fuel cell vehicles and hybrids usually contain relatively small battery packs and have limited electric range when compared with average internal combustion engine vehicles. This fact and the unavailability of extremely high power rapid charge stations at the time of this writing and the associated potential risks to battery health from the extra high power rapid charging, leads most pure battery electric vehicle users to limit their driving to shorter distances and not consider long road trips or interstate or intercountry travel. In limited locations where there are extra high power rapid chargers, they place a large load on the electrical grid, which could overload the system if there is a lot of load in that area of the electrical grid circuit. There is a manufacturer of extra high power rapid chargers, Kanematsu, which has a fast charger with backup battery installed at Portland State University that charges its backup batter at a lower rate and which supplements power from the grid when charging an electric vehicle so as not to put such a large load on the grid. A disadvantage of both fast chargers powered solely from the grid and fast chargers with a battery backup system is that they are large stationary devices that can't be moved to any location where fast charging is needed. Although hybrid vehicles may be used on longer trips, they must rely on their combustion engine, and the actual miles traveled per gallon of fuel consumed is not as favorable as when the electric portion of the system is able to provide sole driving power.
For this reason, there have been aftermarket manufacturers of some plug-in range extender kits to allow extended electric-only driving for hybrids, such as plug-in Prius kits like the one developed by Hymotion. A disadvantage of these kits is that, with current battery technology, they do not add significant range for long trips and is a permanent fixture in the vehicle, adding extra weight and is not versatile in operation with other vehicles to be moved between different models of hybrid vehicles.
There have been some solutions for providing power to EVs in remote locations or even while driving; however, they are usually limited to large, ungainly devices and are almost always tailored to a specific vehicle. This is due in part to the lack of standardization by the builders of electric vehicles. Many different electric vehicles and components use different voltage levels. When a power source is used, it has to be sized to the appropriate voltage level for that device. Just like the battery in one cell phone may not work with another cell phone, the battery pack of one electric vehicle is not likely to work in any other electric vehicle.
In fact, if the safe charging or operating voltage levels of a given system are exceeded, the results can lead to permanent damage or even fire or explosion. U.S. Pat. No. 8,120,310 B2: “METHODS AND SYSTEMS FOR CHARGING ELECTRIC VEHICLES USING SOLAR POWER” describes a two-wheeled road-going electric vehicle trailer that is limited to solar power as the energy source for the electricity it supplies to the electric vehicle. It requires a charging controller to be placed on the electric vehicle, permanent and specific to that vehicle, to accept the power output from the trailer and adjust it to properly supply a safe power level to the electric vehicle. It also requires an additional device, a power converter, to take the power from the solar panels and convert it to a form suitable for the onboard battery backup system or to supply to the charge controller on the electric vehicle. This adds an extra system of complication to the trailer.
Another range extending trailer, Steve Hawkins' RXT-B (Range Extending Trailer-Battery), allows the user to charge it from AC power, but it requires a dedicated electric vehicle charging station to do so, decreasing the flexibility of where you charge it. It also has a fixed voltage output to be compatible with only one model of electric vehicle.
U.S. Pat. No. 5,559,420 entitled “ELECTRICITY SUPPLY UNIT TRAILER FOR ELECTRIC VEHICLES” also requires an off-board charger for its batteries, although the battery pack is removable for quick swapping from the trailer, that requires that there are multiple other battery packs readily available to swap with, requiring greater investment in batteries.
Both the RXT-B trailer and U.S. Pat. No. 5,559,420 can only power electric vehicles and cannot provide auxiliary AC power. U.S. Pat. No. 5,559,420 can vary output voltage, but it requires physically changing battery connections to make more or less series or parallel connections, requiring complicated mechanisms or time consuming labor and only producing a finite number of settings for voltage and maximum current. None of these references suggest having an auxiliary energy supply solution that could accept a wider range of power sources as well as employ a means of easy or even automatic adjustment of the unit's output levels such that it could be used with a variety of electric vehicles and not necessarily require a specific charge controller on the electric vehicle.
Electric vehicle manufacturers usually do not place large battery packs in the electric vehicles because the larger battery packs would add much extra volume and weight and because the majority of driving does not require extreme range. As a result, it is not feasible for most electric vehicle users to use their EV when they do wish to travel long distances. Trailers are almost always frowned upon for electric vehicle use since they add weight, increase rolling resistance, and sometimes more aerodynamic drag.
Known EV trailer designs usually rely on a combustion engine for some or all of the power because the combustion engine fuel allows for a lighter weight and smaller trailer. These trailers are generally designed for a specific vehicle, they are noisy, prone to increased maintenance, produce emissions, and usually achieve poor miles-per-gallon ratings compared to pure battery electric vehicles while still being reliant on a limited fossil fuel source. This is true 100% of the time they are operating because they don't have an alternate onboard energy source such as electric batteries. Two such examples of combustion engine powered generator trailers for extending the range of electric vehicles which have these drawbacks are U.S. patent application Ser. No. 12/557,788: “SELF PROPELLED ELECTRIC VEHICLE RECHARGING TRAILER” and the AC Propulsion BEV RXT-G (Battery Electric Vehicle Range Extending Trailer-Generator) “Long Ranger”. U.S. patent application Ser. No. 12/557,788 has incorporated its own propulsion means so as to offset the added weight by assisting with motive power. With the added electric propulsion source, it adds mechanical complication and more moving parts and increased cost and complexity to have a control unit which provides the right amount of propulsion for the trailer. Again, none of these references suggest being able to have a trailer or other transportable device that could easily be attached to the EV and adjusted to provide the desired power. They further do not recognize that it would be ideal if there were some way for the device to offset its added weight, and if it had the option to use batteries and or other power sources to augment or completely do away with the combustion engine generator.
The following references also share additional disadvantages, U.S. Pat. No. 8,120,310 B2: “METHODS AND SYSTEMS FOR CHARGING ELECTRIC VEHICLES USING SOLAR POWER; U.S. Pat. No. 5,559,420: “ELECTRICITY SUPPLY UNIT TRAILER FOR ELECTRIC VEHICLES”; U.S. patent application Ser. No. 12/557,788: “SELF PROPELLED ELECTRIC VEHICLE RECHARGING TRAILER”; Steve Hawkins' RXT-B (range extending trailer-battery); and AC Propulsion BEV RXT-G (Battery Electric Vehicle Range Extending Trailer-Generator) “LongRanger” share. For example, all of them are in a trailer form, using wheels, and towed behind an electric vehicle, which can add unnecessary size to the overall vehicle assembly and make maneuvering more difficult. They all also have the added weight and bulk of the trailer frame that is required to be strong enough in a low profile form to support the extra load of all of their components and equipment on top of the frame. The last four of five of the trailers listed have little capability for cargo storage, or any other function that common trailers typically perform. This means that a trailer is being towed by the electric vehicle for increased range without the benefit of performing any of the functions that trailers typically perform, such as hauling cargo of general bulk form or of a specialized form that requires a purpose built trailer.